feat(import-window): add window state management to JS

Adds WINDOW_SESSION_STORAGE_KEY, readWindowSessionState(),
window state properties to state object, new element references
in elements object, and persistWindowSessionState().

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/zotero_kb/templates/index.html

@@ -424,8 +424,22 @@
     </main>
 
     <script>
+      const WINDOW_SESSION_STORAGE_KEY = "zotero-kb.import-window";
       const IMPORT_SESSION_STORAGE_KEY = "zotero-kb.import-modal";
 
+      function readWindowSessionState() {
+        try {
+          const raw = window.sessionStorage.getItem(WINDOW_SESSION_STORAGE_KEY);
+          if (!raw) return {};
+          const payload = JSON.parse(raw);
+          return typeof payload === "object" && payload ? payload : {};
+        } catch (_error) {
+          return {};
+        }
+      }
+
+      const windowSessionState = readWindowSessionState();
+
       function readImportSessionState() {
         try {
           const raw = window.sessionStorage.getItem(IMPORT_SESSION_STORAGE_KEY);
@@ -446,7 +460,19 @@
         currentProjectId: null,
         currentCards: [],
         collectionTree: [],
+        isImportWindowOpen: false,
         isImportModalOpen: false,
+        windowX: typeof windowSessionState.x === "number" ? windowSessionState.x : null,
+        windowY: typeof windowSessionState.y === "number" ? windowSessionState.y : null,
+        windowWidth: typeof windowSessionState.width === "number" ? windowSessionState.width : null,
+        windowHeight: typeof windowSessionState.height === "number" ? windowSessionState.height : null,
+        isWindowMinimized: Boolean(windowSessionState.isMinimized),
+        isWindowMaximized: Boolean(windowSessionState.isMaximized),
+        isWindowDragging: false,
+        windowDragStartX: 0,
+        windowDragStartY: 0,
+        windowDragStartLeft: 0,
+        windowDragStartTop: 0,
         selectedCollectionKey: typeof importSessionState.selectedCollectionKey === "string"
           ? importSessionState.selectedCollectionKey
           : null,
@@ -471,18 +497,22 @@
         projectForm: document.getElementById("create-project-form"),
         projectStatus: document.getElementById("project-status"),
         projectList: document.getElementById("project-list"),
-        importModal: document.getElementById("import-modal"),
+        importWindowShell: document.getElementById("import-window-shell"),
-        importModalOverlay: document.getElementById("import-modal-overlay"),
+        importWindow: document.getElementById("import-window"),
+        windowToolbar: document.getElementById("import-window-toolbar"),
         openImportModalButton: document.getElementById("open-import-modal-button"),
-        closeImportModalButton: document.getElementById("close-import-modal-button"),
+        windowMinimizeButton: document.getElementById("window-minimize-button"),
-        importModalProjectLabel: document.getElementById("import-modal-project-label"),
+        windowMaximizeButton: document.getElementById("window-maximize-button"),
-        collectionStatus: document.getElementById("collection-status"),
+        windowCloseButton: document.getElementById("window-close-button"),
-        collectionTree: document.getElementById("modal-collection-tree"),
+        windowRestoreButton: document.getElementById("window-restore-button"),
-        collectionItems: document.getElementById("modal-collection-items"),
+        importWindowMinimizedBar: document.getElementById("import-window-minimized-bar"),
-        selectedCount: document.getElementById("modal-selected-count"),
+        windowProjectLabel: document.getElementById("import-window-project-label"),
-        selectDescendantsButton: document.getElementById("modal-select-descendants-button"),
+        windowSelectedCount: document.getElementById("window-selected-count"),
-        clearSelectionButton: document.getElementById("modal-clear-selection-button"),
+        windowClearSelectionButton: document.getElementById("window-clear-selection-button"),
-        importSelectedItemsButton: document.getElementById("modal-import-selected-items-button"),
+        windowImportSelectedItemsButton: document.getElementById("window-import-selected-items-button"),
+        windowCollectionStatus: document.getElementById("window-collection-status"),
+        windowCollectionTree: document.getElementById("window-collection-tree"),
+        windowCollectionItems: document.getElementById("window-collection-items"),
         currentProjectLabel: document.getElementById("current-project-label"),
         cardList: document.getElementById("card-list"),
         cardDetail: document.getElementById("card-detail"),
@@ -511,6 +541,27 @@
         );
       }
 
+      function persistWindowSessionState() {
+        const fw = elements.importWindow;
+        if (!fw) return;
+        const style = window.getComputedStyle(fw);
+        const width = parseFloat(style.width);
+        const height = parseFloat(style.height);
+        const left = parseFloat(style.left);
+        const top = parseFloat(style.top);
+        window.sessionStorage.setItem(
+          WINDOW_SESSION_STORAGE_KEY,
+          JSON.stringify({
+            x: left,
+            y: top,
+            width: width,
+            height: height,
+            isMinimized: state.isWindowMinimized,
+            isMaximized: state.isWindowMaximized,
+          })
+        );
+      }
+
       function setStatus(target, message, isError = false) {
         target.textContent = message || "";
         target.classList.toggle("error", Boolean(isError));